As bans against same-sex marriage crumble and public opinion on the issue shifts rapidly, some Republicans are pushing the party to drop its opposition to same-sex unions, part of a broader campaign to get the GOP to appeal to younger voters by de-emphasizing social issues.

This month, the Nevada Republican party dropped statements on marriage from its party platform, making it the second state party in the nation to do so after Indiana's GOP quietly jettisoned its plank in 2012. A gay-rights group last week launched a $1 million campaign to get the national party to remove from its platform a definition of marriage as between a man and a woman, while a group of major Republican donors is pushing for the GOP to become more supportive of gay rights across the board.

"There are people with sincerely held beliefs on both sides of the marriage issue, and that seems to be where the party is heading," said Jeff Cook-McCormac, an adviser to the American Unity Fund, which has been financed by wealthy donors to push the GOP to back gay rights. "The Republican Party in Nevada is doing something that I think we're going to see a lot more of, which is appealing to the things that unite Republican voters across the country - bread and butter issues."

But social conservatives warn that if the GOP abandons its core moral principles, it may also lose loyal voters.

"It is very much a mistake for the GOP to step away from marriage. The rank-and-file Republicans, mainstream Republicans, very much believe marriage is between a man and a woman," said Chris Plante, spokesman for the National Organization for Marriage. "For the GOP to give in to elites, to promises of money, and to progressives within the party is the wrong thing. It's bad politics. Marriage is a winning issue."

The greatest test will come in Nevada, a swing state where the state party also dropped its opposition to abortion during its biannual convention on April 12. The push arose from Clark County, home to libertine Las Vegas and three-quarters of the state's population.

"Younger people believe they're getting screwed by the Democrats on fiscal issues, and screwed by Republicans on social issues," said Nick Phillips, the Clark County party's political director. "Take that away, and you've got a party you can get behind."

The state's Republican governor, Brian Sandoval, supports abortion rights, recently decided to drop the state's defense of a lawsuit challenging its same-sex marriage ban, and is so popular that no significant Democrat is challenging him for re-election this year.